An organic solvent is used in coating compositions of various coatings such as overcoat agent for plastic films, printing ink and coating material. Due to the fear that a volatile organic component volatilizing from the organic solvent affects a worker, the process, production apparatus and the like involving the handling of such a coating composition are complicated to induce a large load in view of operation and equipment. Also, the volatile organic component imposes a heavy load such as air pollution on the environment. Accordingly, from the standpoint of reducing the economical load and environmental load, it is recently demanded to decrease the amount of the organic solvent used in the coating compound.
For example, there has been proposed an active energy ray-curable aqueous resin composition comprising a vehicle and water as essential components, in which the vehicle is a reaction product comprising a hydroxyl group-containing acrylic acid ester, an organic polyisocyanate and (C) a polyethylene glycol containing at least one hydroxyl group (see, JP-A-6-271632 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) and JP-A-6-287260).
However, when a layer is formed on a substrate by curing a coating composition containing water, if the adhesion between the substrate and the cured layer is low, the scratch resistance decreases. A coating composition ensuring higher scratch resistance optimal for surface coating of an article is being demanded.